When deploying wireless communication networks, there is a balance between coverage and capacity. On the one hand, a few large cells can provide great coverage but at a cost of reduced capacity. On the other hand, a scenario with many small cells creates better capacity and throughput, but may not provide the desired coverage. Hence, there is often a combination of larger cells to provide sufficient capacity with smaller cells to provide better capacity.
However, when the cells get too small, wireless terminals moving in the network cause a great number of handovers which causes significant overhead. Moreover, providing coverage indoors using many small cells can be quite costly, with a radio base station for each such small cell.
One solution to this problem is to use radio heads being located remotely from a radio base station, where several radio heads connected to the same radio base station share the same cell. In this way, a single radio base station can provide coverage in different parts of the building by placing the radio heads appropriately. Moreover, the wireless device can move between the coverage of different radio heads while staying within the same cell, thus avoiding causing handovers.
The cable between the radio base station and the remote radio heads, however, is often susceptible to interference. There is currently no known way to detect such interference, and no way to take action to reduce any effects of such interference.
U.S. Pat. No. 5,809,395 A discloses a multichannel radiotelephony system providing two way cordless communications with a plurality of multichannel transceivers portable within a coverage area comprised by a plurality of cells, each associated with a base station and antennas, such as to permit channel frequency reuse in cells within the coverage area.
EP 2 385 672 B1 discloses an apparatus including a transmitter configured to transmit symbols to one or more receivers via a plurality of communication channels of a physical communication link. The transmitter is configured to estimate a phase of one or more off-diagonal elements of a channel matrix for the physical communication link based on values of signal-to-interference-plus-noise ratios at the one or more receivers.
EP 2 442 488 A1 discloses a device for detecting a physical link and a method thereof, wherein a detecting end sends a detection signal to a detected end; the detected end returns the detection signal to the detecting end after processing the detection signal that is received; the detecting end re-processes the detection signal that has been processed from the detected end, and determines whether a physical link failure occurs according to the detection signal that is re-processed.